Updated August 2026 · Top 25 of 71 lakes with a Secchi reading
Clearest Lake in Alabama: Top 25 by Secchi Depth
Sinl Lake in Lawrence County is the clearest lake in Alabama by Secchi depth, at 14.5 ft. Mapped and ranked below: the 25 clearest of 71 Alabama lakes with a Secchi reading. Secchi depth is shown, not scored: the letter grades nutrients and algae, so a clear lake can be unrated or carry a lower grade than a murkier one.
How clear are Alabama's clearest lakes?
From 14.5 ft at Sinl Lake to 5.3 ft at #25, Ncht Lake; the median of the 25 is 6.5 ft.
| # | Lake | County | Secchi depth | Grade | Area |
|---|---|---|---|---|---|
| 1 | Sinl Lake | Lawrence | 14.5 ft | A | — |
| 2 | Inlb Lake | Blount | 11.9 ft | A | — |
| 3 | Smiw Lake | Winston | 11.5 ft | A | — |
| 4 | Mare Lake | Randolph | 11.5 ft | A | 10,661 acres |
| 5 | Mare Lake | Elmore | 10.6 ft | A | — |
| 6 | Smith Lake | Cullman | 9.8 ft | NR | — |
| 7 | Ellf Lake | Franklin | 8.8 ft | A | — |
| 8 | Rlhr Lake | Randolph | 8.5 ft | C | — |
| 9 | Tust Lake | Tuscaloosa | 7.7 ft | A | — |
| 10 | Lake Martin | Tallapoosa | 7.5 ft | NR | — |
| 11 | Yate Lake | Tallapoosa | 7.4 ft | A | 40,000 acres |
| 12 | Bclm Lake | Mobile | 6.9 ft | A | — |
| 13 | Tennessee River Lake | Jackson | 6.5 ft | D | — |
| 14 | Tenr Lake | Limestone | 6.5 ft | C | — |
| 15 | Albd Lake | DeKalb | 6.5 ft | D | — |
| 16 | Tlst Lake | Talladega | 6.3 ft | C | — |
| 17 | Cahc Lake | Cleburne | 6.3 ft | C | 84 acres |
| 18 | Tenr Lake | Lauderdale | 6.1 ft | NR | — |
| 19 | Lake Andrews | Houston | 5.9 ft | A | 1,540 acres |
| 20 | Thue Lake | Elmore | 5.8 ft | A | 574 acres |
| 21 | Jore Lake | Elmore | 5.7 ft | C | — |
| 22 | Geoh Lake | Barbour | 5.7 ft | NR | — |
| 23 | Mitc Lake | Chilton | 5.4 ft | C | 5,850 acres |
| 24 | Ctmc Lake | Cullman | 5.4 ft | D | — |
| 25 | Ncht Lake | Tuscaloosa | 5.3 ft | A | — |
Sources and method
- Secchi depth: Median of each lake's EPA Water Quality Portal readings, sampled January 2012 to June 2026, in feet. For 21 of these 25 lakes the submitting agency is Alabama DEPT. OF Environmental Management - Water Quality DATA. Portal: EPA Water Quality Portal.
- Grade: A–F water-quality grade from nutrient and algae sampling (total phosphorus and chlorophyll-a) against the lake's EPA ecoregion classes, where enough recent samples exist to support one; the dashed NR mark otherwise. Clarity is not part of the grade, which is why a clear lake here can be unrated or carry a lower letter than a murkier one.
- Area: state agency lake surveys and, for reservoirs, US Army Corps of Engineers National Inventory of Dams records, in acres at normal pool. A dash means no record carries one.
- Map pins: all 25 table rows, colored by grade. No other lakes are plotted.
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Frequently Asked Questions
What is the clearest lake in Alabama?
Sinl Lake in Lawrence County is the clearest lake in Alabama by Secchi depth, at 14.5 ft. Secchi depth is measured by lowering a black-and-white disk until it disappears from view; a deeper reading means clearer water. Sinl Lake holds an overall water-quality grade of A.
How clear are Alabama's 25 clearest lakes?
They span 5.3 ft to 14.5 ft of Secchi depth, with a median of 6.5 ft. Sinl Lake leads by 2.6 ft. Elmore County has 3 of the 25; the rest are spread across 18 other counties. 21 of the 25 carry an A–F grade; the other 4 are not rated because their recent sampling does not support a letter.
How is water clarity measured?
Water clarity is measured by Secchi depth, named after the 19th-century Italian astronomer Pietro Angelo Secchi who developed the method. A standardized black-and-white disk is lowered into the water on a rope; the depth (in feet or meters) at which the disk disappears from view is recorded. Greater Secchi depth means clearer water, usually a sign of low sediment, low phosphorus, and limited algae growth. The figure for each lake here is the median of its readings.
What makes a lake clear?
Lake clarity is driven by three factors: low suspended sediment (clay, silt), low nutrient load (especially phosphorus, which fuels algae), and low chlorophyll-a (active algae biomass). Deep lakes with rocky basins and forested watersheds tend to be clearest because they take in little soil runoff and few nutrients. Shallow lakes in farmed watersheds are typically less clear because they receive more sediment and fertilizer runoff.
Is the clearest lake the cleanest?
Not always. Clarity (Secchi depth) is measured and shown; the letter grades nutrients and algae (total phosphorus and chlorophyll-a) against that lake’s EPA ecoregion classes. A lake can be very clear but still have elevated phosphorus that just hasn't bloomed yet. See our companion cleanest-lakes ranking for Alabama for the nutrient-and-algae list.
Where to stay near Alabama's clearest lakes
Planning a trip? Jump to live cabin, resort, and hotel availability near Alabama's clearest lakes.
More on water clarity
The clearest lakes in America, ranked by measured Secchi depth in feet from EPA monitoring data — and why the famously clear lakes are missing.
What a Secchi depth reading measures, how many feet counts as good clarity, and why clear water is not always clean — with readings from graded lakes.
County-by-county Secchi champions: the clearest measured lake in each county, the murkiest county winners, and why a county title is not a national one.
Surveyed maximum depth against A–F nutrient-and-algae grades: the pattern, the shallow lakes that still grade an A, and why land use beats bathymetry.